Arylsulfur pentafluorides compounds are used to introduce one or more sulfur pentafluoride groups into various organic molecules in the development of medicines, agrochemicals, and new materials. In particular, arylsulfur pentafluorides have been shown as useful compounds (as product or intermediate) in the development of liquid crystals, in bioactive chemicals such as fungicides, herbicides, and insecticides, and in other like materials [see Fluorine-containing Synthons (ACS Symposium Series 911), ed by V. A. Soloshonok, American Chemical Society (2005), pp. 108-113]. In particular, aromatic compounds having two or more pentafluorosulfanyl groups (SF5) are of increased interest because they are more useful in these applications as compared to aromatic compounds having one pentafluorosulfanyl group. Presently, few such compounds have been successfully synthesized, for example 3,5-bis(pentafluorosulfanyl)nitrobenzene, 3,5-bis(pentafluorosulfanyl)aniline, 1,3,5-tris(pentafluorosulfanyl)benzene, and 1,2,4-tris(pentafluorosulfanyl)benzene have been synthesized to date, illustrating the difficulty of their production. As such, and as discussed further herein, conventional synthetic methodologies to prepare aromatic compounds having two or three pentafluorosulfanyl groups have proven difficult to prepare and are a concern within the art.
Conventionally, aromatic compounds having two or three pentafluorosulfanyl groups are synthesized by one of the following methods: (1) fluorination of a poly(nitrobenzenedisulfide) with AgF2 [see J. Am. Chem. Soc., Vol. 82 (1962), pp. 3064-3072]; or (2) reaction of SF5Cl with acetylene, followed by bromination with Br2 under hν irradiation, dehydrobromination, and reduction with zinc, giving pentafluorosulfanylacetylene (HC≡CSF5). The pentafluorosulfanylacetylene is then reacted with Co2(CO)8, giving a complex, Co(CO)4(HC≡CSF5)3, and the complex decomposing in the presence of Br2 to give 1,2,4-tris(pentafluorosulfanyl)benzene [see Chem. Ber., Vol. 119, pp. 453-463 (1986)]. Photoreaction of pentafluorosulfanylacetylene in the presence of SF5Cl gives 1,3,5-tris(pentafluorosulfanyl)benzene [see Chem. Ber., Vol. 119, pp. 453-463 (1986)].
Each of the above synthetic methods has one or more drawbacks making them industrially impractical. For example, the former method provides a very low yield and requires an expensive reaction agent, AgF2. The latter method requires an expensive and toxic gas, SF5Cl, and many reaction steps to reach a final product at low yield.
In addition, it has been reported that related compounds, p- and m-(pentafluorosulfanyl)nitrobenzene, were prepared by reacting a bis(nitrophenyl) disulfide with molecular fluorine (F2), CF3OF, or CF2(OF)2 [Tetrahedron, Vol. 56, 3399-3408 (2000); USP 2004/0249209 A1]. However, F2, CF3OF, and/or CF2(OF)2 are extremely toxic, corrosive, and dangerous gasses and their handling is expensive from the standpoint of gas production, storage and use. In addition, synthesis methods that require the use of F2, CF3OF, and/or CF2(OF)2 are limited to the production of deactivated (pentafluorosulfanyl)aromatic compounds, such as nitro-substituted (pentafluorosulfanyl)aromatic compounds, due to their extreme reactivity, which leads to side-reactions such as fluorination of the aromatic rings when not deactivated. It has also been reported that (pentafluorosulfanyl)benzene and p-(pentafluorosulfanyl)toluene were prepared by reacting diphenyl disulfide and di(p-tolyl) disulfide with XeF2, respectively [J. Fluorine Chem., Vol. 125 (2004), pp. 549-552]. However, this method requires an expensive reagent, XeF2. Therefore, problems with the production methods known for the pentafluorosulfanylaromatic compounds have made it difficult to prepare the material in an industrially safe, cost effective and timely fashion.
The present invention is directed toward overcoming one or more of the problems discussed above.